Carbon wheel, rough internal rim finish


I’ve just unboxed a new set of carbon wheels and all looks good apart from the finish on some of the internal rim bed of the wheels, particularly the rear wheel. They are WTO 60.

I can’t find anything on web searches from anyone mentioning a similar situation. I’ve been in touch with the retailer and waiting on them to come back.

While it’s most prominent on the rear wheel, it’s also there on the front wheel. On the front wheel it seems to be around the seem line where the wheel joins together. So it may possibly be that the builder of the rear wheel was over enthusiastic in the sanding?

Is this par for the course on carbon rims?

Couple of pics attached - Rear wheel

Front wheel

I don’t see what you are referring to. All I see is the carbon weave. That seam looks pretty good to me. Maybe what you are saying isn’t showing up on camera?

Most of the rim is black, but section pictured is a white colour and looks like it has been sanded. Rather than the usual smooth carbon finish of the rest of the wheel. Its the internal rim rather than the braking surface.

I have a set of WTO60s and can confirm that the internal finish is different to the mirrored external finish. Think that the external is moulded and the internal machined?

Less sure about the random fibres sticking out the side - don’t think I noticed that on mine?

Thanks kevstraining. Do you recall if just one section of the inside rim of each wheel was a different finish to the rest of the inside. It definitely looks like sanding just in one area of the inside, so may just be where the the join line is where the wheel is bonded to smooth the join? wouldn’t expect the inside to get the same polished finish as the outside. It’s just this once section on each wheel that looks weird

Those fibers are just dust etc. I only spotted them on the pic after I’d taken it. they all wiped off with my hand when rubbed.

These pics might show it a bit more clearly. The darker area is consistent with the rest of the inside of the rim. The white bit is where it’s been sanded/rubbed down, Its on the inside of the rim wall and the main rim where rim tape would go if needed.

It’s difficult to see from the pics, but you are likely seeing the sections where they need to sand to remove the “parting line” in the rim. This is a point where the inserts used to created the inner rim shape join and meet to form the full circular shape. There should be locations like this about 90* thru 180* apart (depends on total sections of the rim bed tool) to match the actual sections.

Generally speaking some level of finishing like sanding is required to remove the small transitions and irregularities that exist from these tooling joints. Nothing of concern from what I can tell.

ETA: Snagged a pic from a video, and this one shows what appears to be 3 sections, 120* angle apart.

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It’s probably a minor spot of lazy finishing at the factory but I don’t think it’s going to affect the ride one bit. I’d ride it rather than return it but I understand that when you pay that kind of price for wheels you expect perfection. It’s good to remember that all these carbon products are at least partially hand made and/or hand finished.

From experience, what you don’t want is any sharp edges where the lower tire sidewall is up against the inner rim. Had that once on an Enve 5.6 disc and it ended up cutting into the tire. Enve was great and replaced immediately. The fibers sticking out on the upper side of the outer rim? That just seems wrong, and would likely bother me enough to file a claim or exchange before riding.

heh, he said that was dust and wiped off, but looks like weird dust to me. Looks like fibers as you said.

Thx, I see that post now.

Recommend using a damp, soft cloth to wipe down the wheels entirely and see what it looks like after.

Haven’t heard back from the retailer, but I’ve contacted the local Campagnolo service centre for them to confirm if all is in order or something is unusual. I suspect its a late cleaning up of a rough surface and more visual than anything structural, but best to check it out than find out on the road!!!

Have also asked them about the fibres. All seem to be on the brake track and while most rub off a couple did seem to be stuck/park of the brake track.

I’m going to check out a set of Fulcrum wheels over the weekend, which are basically Campag wheels, to see if they show a similar internal finish at joins.

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Let us know what you find out!

Blown up digital pics of carbon bike parts often lead to all sorts of worry.

They are some how cutting those little slots out of the brake track. Laser? It looks like a few pieces left over.

I’d be riding these wheels already!

Checked out the fulcrum wheels over weekend and they have the same thing going on with them, IE some sanding down at the internal joint. Although on the fulcrums it was a much lighter job and wouldn’t notice unless looking for it. So looking more and more like normal manufacturing, with just whoever was doing the finishing/QC on the Bora’s being a little over eager on their sanding!!

Tyres should arrive today, so should be able to set them up for a spin this week.

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Retailer has doubled checked it with Campagnolo. Confirmed that its just normal machining, just a bit more on this particular set. but is normal and not a problem.

Tyres and cassette arrived yesterday and got them setup tubeless easily enough. GP5000 took a bit of persuading but got them on without tools in about 5 mins.

All set to go racing on later in the week.

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Are they the original “TL” GP5k or the new “TR” version?

I’m not able to fit "TL"s sans tools onto my WTOs (not until they stretch a bit anyway) so would be nice to hear that the "TR"s are easier.

They were the TR. Harder than a normal tyre but doable. Seated grand with track pump as well